Action of acid on oligoribonucleotide phosphotriester intermediates. Effect of released vicinal hydroxy functions.
AUTOR(ES)
Reese, C B
RESUMO
When 2'-O-methoxytetrahydropyranyl-5'-O-(9-phenylxanthen-9-yl) uridylyl-(3'----5')-(2',3'-di-O-acetyluridine) 2-chlorophenyl ester (9) is treated with zinc bromide in dichloromethane-propan-2-ol (85:15 v/v) at room temperature, under stringently anhydrous conditions, the corresponding 5'-unblocked dinucleoside phosphate (10) is obtained in 86% isolated yield; however, when no special precautions are taken to exclude moisture, (10) is obtained in only 72% yield. The removal of the 5'-O-(9-phenylxanthen-9-yl) protecting group from (10) with a protic acid (phenyl dihydrogen phosphate) appears to be much less selective and efficient. 80% Acetic acid promoted removal of the methoxytetrahydropyranyl protecting group from the isomeric fully-protected uridylyl-(3'----5')- and uridylyl-(2'----5')-uridine derivatives [(11) and (21c), respectively] leads to virtually identical mixtures [Figures 1a and 1b, respectively] of the partially-protected dinucleoside phosphates [(14) and (15)], 2',3'-di-O-acetyluridine (8), 5'-O-acetyluridine 2',3'-cyclic phosphate (16), and 5'-O-acetyluridine 2'(3')-phosphates [(18) and (17)].
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=321860Documentos Relacionados
- Synthesis of ppTppp via phosphotriester intermediates.
- Synthesis of 3'-phosphates of diribonucleoside monophosphates via phosphotriester intermediates.
- Polymer supported DNA synthesis using hydroxybenzotriazole activated phosphotriester intermediates.
- New effective method for the synthesis of oligonucleotides via phosphotriester intermediates.
- Mechanism of action of AC-1370 on phagocyte functions.